GM has filed a patent application a variable displacement valvetrain system with rocker shaft porting and insert sleeves for engine cylinder deactivation.

Since a Pontiac V-8 is a pushrod engine (instead of being an overhead cam design), it afforded us the opportunity to explore a different rocker-arm ratio and determine its impact on power. As built, ...

Any gearhead worth his or her salt knows that whether it's a SOHC, DOHC, or OHV engine, the camshaft is considered the brain of a four-cycle internal combustion power plant. The camshaft's profile ...

In the valvetrain of your typical pushrod engine, the rocker arm is a critical component that also is an excellent tuning device. To properly tune with rocker arms, though, you need to understand how ...

Drag racers have been searching for tricks to gain horsepower since day one, and there are lots of ways to do it without spending a tremendous amount of time or money. One of the biggest downfalls of ...

The typical four-stroke engine is made up of hundreds of parts. These parts are all designed and engineered to work together to make a prescribed amount of power, torque, engine longevity, and other ...

A recently filed patent details a new GM cylinder deactivation system that appears to be heading to the next-gen V8 engines ...

The engines of yesteryear were pretty simple, with tappets clackity-clacking away on cam lobes, opening valves, and making a ruckus while doing it. Mechanical lifters were adequate for valve operation ...